This invention relates to the removal of particulate from a drilled or cut surface. More particularly, the subject invention concerns a system and method useful for removing particulates created from drilling pharmaceutical tablets, said system and method being characterized by effectively removing the particulates from the site of tablet drilling, collecting said particulate, and transporting the particulate to a remote location without altering the position of the tablet.
Industrial drilling and cutting presents an ever-present problem concerning the removal of particulate matter formed by the drilling or cutting process. In manual and automated drilling and cutting processes, the particulate usually serves no useful purpose. In many situations, the particulate creates an undesirable environment around the drilling or cutting site and may interfere with subsequent drilling in a repetitive drilling or cutting situation. When the drilling relates to industrial processing of precious metals, e.g. gold or platinum, it is usually desirable to collect and reprocess the collected particulate. In other instances, where the waste particulate has little to no value it is desirable to remove and dispose of the created particulate.
An example of particulate matter that is desirable to remove and dispose of ocurrs in the pharmaceutical industry. Much effort has been devoted to the continued development and improvement of controlled release pharmaceutical formulations. The use of controlled release formulations can facilitate patient compliance with a particular dosing regimen. One known method employed for producing controlled release tablets is to provide a coating surrounding a tablet core containing an active ingredient, and to incorporate in that coating a hole or plurality of holes to allow fluid to penetrate through the membrane. The active ingredient in the tablet core is dissolved or suspended by the fluid penetrating the membrane and then exits the tablet through the hole in order to provide bioavailability of the active ingredient. It is important for consistent bioavailability that the hole has a precise size and shape. Accordingly, the procedure for hole formation must be precisely controlled such that each tablet is formed with a hole or holes that are consistently reproducible in diameter, depth and location on the tablet in order that the tablets exhibit substantially similar characteristics regarding drug release.
The particulate matter formed during the drilling of these holes can interfere with the precise formation of the hole. Once a tablet is drilled, the particulate matter that is created by the drilling process can become airborne in the vicinity of the drilling. This poses two problems. First, the particulate matter may be deposited on or near the laser lens, which may interfere with subsequent drilling of tablets. If the laser firing is not consistent or the precision is not reproducible for each tablet, the uniformity in size, shape, and depth of the holes that are formed can be negatively affected. Current Good Manufacturing Practice demands uniformity of drug delivery. If the holes cannot be drilled in a consistent and reproducible manner, it will alter the uniformity of delivery.
Another problem that can arise in the tablet drilling process is that the resulting particulate matter can settle back onto a tablet surface or resettle into the hole, which has been drilled into a tablet. Resettling of particulate matter into a hole that has been drilled may alter the release characteristics of the tablet. This also can result in lack of uniform release among tablets that are otherwise identical. Therefore what is needed is a means for removing the particulate matter from the region of drilling, and transporting or collecting of the particulate matter away from a tablet after it has been drilled.
Machines which are suitable for the laser drilling of tablets are described in U.S. Pat. Nos. 5,294,770, 5,399,828, and 5,783,793, which are incorporated herein by reference. Of the machines commercially available, great effort has been taken to ensure the precision, accuracy and reproducibility of the laser mechanism. However, the processing factor of particulate removal from the drilling site has been neglected in currently available laser drilling machines.
The subject invention concerns an apparatus and system for removing particulate created from a drilled or cut surface. The subject invention has many applications such as industrial drilling of precious metals, metals, precious stones, stones, pharmaceutical tablets, and any other setting where particulate is created from drilling or cutting. The term xe2x80x9cdrillingxe2x80x9d refers to any method in which matter is removed to create an orifice. These drilling methods may include, but would not be limited to drilling with a drill bit, boring, or using a laser to create a hole. The term xe2x80x9ccuttingxe2x80x9d is intended to include any manner in which substrates are severed. Therefore, xe2x80x9ccuttingxe2x80x9d would include, but would not be limited to, using a blade, laser, or any other means by which substrates are severed. It is contemplated the subject invention is useful for any setting where particulate matter is created.
One embodiment of the system according to the subject invention includes:
A system for removing particulate formed by a drilling or cutting device, said system comprising:
a) a compressed gas source directed to a drilling or cutting site to mobilize residual particulate matter created by the drilling or cutting device; and
b) an apparatus for receiving, transporting and collecting, and transporting said residual particulate away from said drilling or cutting site.
The apparatus is a vacuum chamber having first an second ends, wherein said first end is connected to a vacuum source; and said second end is for receiving said residual particulate materiai.
In the system, airflow may be negative pressure created by a vacuum source or positive pressure created by a directed stream of compressed gas. The system further comprises a directed stream of compressed gas in which said the direction of the compressed gas is aimed at said drilling site. The compressed gas may be compressed air or inert gas. The term xe2x80x9cinert gasxe2x80x9d refers to noble gasses, nitrogen, any combination thereof, or any non-reactive gas or mixture of gasses. In a preferred embodiment, nitrogen is the compressed gas.
The system further provides for collecting particulate created during drilling or cutting. The term xe2x80x9ccollectingxe2x80x9d is meant to include removing, transporting and collecting the created particulate. The system for collecting said particulate material further comprises, a vacuum chamber having a first end connected to a vacuum source and a second end which has at least one receiving inlet for receiving said particulate material. The vacuum chamber is formed with receiving inlets such that they may be placed above, below or above and below the surface of the drilled tablet.
It is an object of this invention to provide for an apparatus and method for removing and collecting particulate matter created from a drilling or cutting site.
It is a further object of this invention to provide an apparatus for removing particulate matter without disrupting the precision and accuracy of the drilling or cutting process or the position of the surface to be drilled or cut.
It is another object of this invention to provide an apparatus for removing particulate matter as soon as it is formed in order to prevent any particulate matter from redepositing or resettling on the drilled or cut surface during processing.
It is still a further object of this invention to provide an apparatus for transporting the removed particulate material away from the site of drilling or cutting.
It is still a further object of this invention to provide an apparatus for collecting the removed particulate material in a pharmaceutically acceptable manner for disposal. A pharmaceutically acceptable manner would be a manner such that no materials or methods are present that will adulterate the integrity of pharmaceutical products.
It is another object of this invention to provide a method by which particulate matter from drilled pharmaceutical tablets are collected and transported away from the site of drilling using the apparatus and system of the subject invention.